Kunitz-type neurotoxin MitTx-alpha is a 84-residue protein from Micrurus tener tener. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: G9I929.
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The mean pLDDT of this model is 83.3 (confident overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 42% |
| 70 to 90 | Confident: backbone generally right | 41% |
| 50 to 70 | Low: treat with caution | 18% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
MitTx, a heteromeric complex between Kunitz- and phospholipase-A2-like proteins, potently, persistently and selectively activates rat and chicken acid-sensing ion channel ASIC1 (PubMed:22094702, PubMed:24507937). Both alternatively spliced rat isoforms ASIC1a and ASIC1b are activated, with a higher potency for ASIC1a (EC(50)=9.4 nM) vs ASIC1b (EC(50)=23 nM) (PubMed:22094702). The rat ASIC3 subtype is also sensitive to the heterodimer, but with a lower potency (EC(50)=830 nM) (PubMed:22094702). On rat ASIC2a, the toxin shows a very weak activation, but produces a remarkable potentiation (>100-fold) of protons when the extracellular pH drops below neutrality (PubMed:22094702). Moderate and…
Heterodimer of an alpha (Kunitz-type) and a beta (phospholipase A2 homolog) chains; non-covalently-linked
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 4NTW | X-ray | 2.07 Å | B=25-84 |
| 4NTX | X-ray | 2.27 Å | B=25-84 |
| 9E4I | EM | 2.33 Å | D/F/H=25-84 |
| 4NTY | X-ray | 2.65 Å | B=25-84 |
| 9E4J | EM | 2.87 Å | D/F/H=25-84 |
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